The process for granulating a powder material normally consists of a series of distinct steps. In particular, this production process includes a first wet granulation step which allows the product to form rough and irregular agglomerates.
These agglomerates then usually undergo a milling process to reduce and homogenize the dimensions of the agglomerates.
The process concludes with a dry granulation step which also helps to dry the finished product.
A granulation device which carries out this process typically consists of separate units, each performing a specific step of the production process.
Each step in the process is carried out by processing measured doses of material, one after another. More specifically, a dose of material is fed into a first wet granulation unit, where it is processed. At the end of this step, the product is discharged from the first unit and fed into a second unit for the milling step.
On conclusion of the milling step, the second unit is unloaded and the product is fed into a third unit for the dry granulation step, completing the production process.
It should be noted that, depending on the type of material, the granulation process can be carried out excluding at least one of the above-mentioned steps.
For example, some products do not need to be milled while in other cases only the wet granulation and milling steps are necessary.
Known granulation device do, however, present some drawbacks.
First of all, the known devices carry out powder product granulation in a discontinuous manner. In fact, each dose of powder is processed independently from the subsequent dose, with a certain time interval between one production cycle and the next.
It is, however, sometimes necessary to have a more constant production of granulated product, avoiding the typical interruptions of the known devices.